| 摘要 |
PURPOSE: To provide a speed controller for a wound-rotor induction motor of which the detecting speed is not deteriorated by the secular change, etc., by detecting the rotating speed of a wound-rotor induction motor without using any mechanical speed detector by electrically detecting the rotating speed from the secondary voltage of the motor. CONSTITUTION: The primary winding of a wound-rotor induction motor 1 is connected to an AC power source 5 and a power rectifier 3 which converts the AC power outputted from the secondary winding of the motor 1 into DC power, power inverter 6 which regenerates the AC power by inverting the DC power into the AC power, and speed control means 10 which controls the rotating speed of the motor 1 by controlling the inverter 6 by comparing the DC power with fed-back signals are provided. Therefore, a speed detecting means 18 which finds the slip frequency fs of the motor 1 from the period ts of the secondary voltage of the motor 1 outputted from the secondary winding and the rotational frequency fn of the motor 1 by subtracting the slip frequency fs from a fixed frequency f1 is provided and the rotational frequency fn is used as a speed feed back signal. |
